This invention relates to improvements in a pattern used to cast a coupler for a railway vehicle and, more particularly, to providing such a coupler having an increased bottom wall thickness both forwardly and rearwardly of a plane coinciding with the horn line of the coupler to strengthen the coupler casting and facilitate the use of interchangeable head and shank pattern portions on a pattern plate used to mold foundry sand.
As is known in the art, various different forms of standard type couplers are used to couple together railway vehicles. The standard forms of E-type, E/F-type and F-type couplers include a unitary casting consisting of two major component parts, namely a coupler head and a coupler shank. The horn line is a transverse plane conventionally used as a demarcation between the coupler head and the coupler shank. The bottom wall, forwardly of the horn line in the coupler head and rearwardly from the horn line in the coupler shank. is a critical area where cracks and even failure of the metal occur because of service stress and fatigue. Spaced by a relatively short distance that varies with the particular type of coupler casting, the bottom wall is provided with a cast recess wherein a wear plate is attached to engage a coupler carrier. The bottom wall from the lock chamber in the coupler head to the recess in the shank for the wear plate is not uniformly thick because the bottom wall in this area is a transition wall between the coupler head and coupler shank. The thickness of this portion of the bottom wall is also a function of the core member used to form the lock chamber and other internal surfaces in the coupler head. The lock chamber is formed by a core which also extends along the shank and forms a hollow section therein.
In application Ser. No. 815,325, filed July 13, 1977 and assigned to the same Assignee as this application, a novel core assembly is disclosed to enable the use of interchangeable core members that are joined together along a parting line in the coupler shank at a closely-spaced location from the horn line. The outer wall surfaces of the core members at the parting line are contoured so that protrusions are produced on the inside wall surface of the casting. These protrusions extend forwardly toward and beyond the horn line and rearwardly along the coupler shank.
The increased thickness to the shank walls produced by these protrusions provides added strength and fatigue resistant properties. However, the bottom wall forwardly and rearwardly of the horn line is also strengthened in a different manner according to the present invention. The area of the bottom wall presently under discussion has an outer surface contour which is modified according to the present invention so that it is substantially planar from the usual depending spaced-apart rotary shaft walls at the bottom of the coupler head and extending rearwardly along the casting to the recess forming the site for a wear resistant member. In the past, the outer surface of this portion of the bottom wall had a relatively large concave surface across the width of the bottom wall that blended forwardly with the rotary shaft wall.